The isotope ratios prove that the Moon is definitively as old as the Earth. Furthermore, we have precambrian fossils that show the course of the tides (which, as you should know, are caused primarily by the Moon) and how the day length has increased over the aeons due to the Moon slowing down the rotation.
Furthermore, humans are definitively not of extraterrestrial origin, having extensive continuity with terrestrial life, from their extensive fossil record and the undeniable similarity to their close living relatives - the apes - to being unambiguous placentarians, mammals, amniotes, tetrapods, chordates, metazoans, eukaryotes… to having exactly the same fundamental biochemistry as the rest of terrestial life.
Why should we take the word of some guy in another galaxy two and a half million light years away over the evidence we can gather here in situ? Also, are these “Andromedans” the only sapient life in this galaxy of approximately one trillion of stars, twice as many as our own? Do they not have a name for their species of their own?
Also, everyone knows that Orions are green, not grey.